Craterellus atrocinereus is a rare Craterellus from California and Oregon, USA. It is currently known from approximately 20-30 locations, from a habitat in decline. The extent of occurrence is is large (133,181 km2), but being restricted to only a limited number of sites the area of occupancy is small (minimum 80-120 km2, and while this may be an underestimate it is unlikely to exceed 2,000 km2). Therefore, it partially meets the requirements for listing as threatened under criterion B2, and is assessed as Near Threatened.

Craterellus atrocinereus was historically referred to by the European species, C. cinereus (Thiers 1985, Arora 1986).

The distinct western North American entity was described from a Type collection made in Santa Cruz County, California, USA (Frank 2015).

Craterellus atrocinereus is a rare Craterellus from California and Oregon, USA. Currently known from ~25 locations, from a habitat in decline.

Craterellus atrocinereus is known from Santa Cruz County, California, USA, north into Oregon; but reports are highly disjunct across this range, with reports from approximately 20-30 locations. The extent of occurrence is is large, at 133,181 km2, but being restricted to only a limited number of sites the area of occupancy (AOO) is small with a minimum AOO of 80-120 km2. While this may be an underestimate it is unlikely to exceed 2,000 km2.

The distribution of this species is widespread, but it is rarely reported, and populations are highly disjunct.

Currently it is known from c.25 locations (exact locations are hidden on a few records, and this number could represent anywhere from 20-30 distinct subpopulations) (iNaturalist 2021, Mushroom Observer 2021, and MyCoPortal 2021, where many are listed as Craterellus cinereus).

Data to fully assess population trends is lacking, but it is likely declining. Stand replacing fires, especially in the southern portion of the range have drastically altered habitat, likely making it ill-suited for Craterellus atrocinereus. As has the decline of Tanoak, and to a lesser extent, live oak, due to the introduced pathogen, Sudden Oak Death (Phytophthora ramorum).

Craterellus atrocinereus is ectomycorrhizal with hardwoods; especially Tanoak (Notholithocarpus densiflorus), Coast Live Oak (Quercus agrifolia) and Oregon White Oak (Q. garryana). Often scattered in small clusters or groups, fruiting in late winter and spring.

Local populations in the San Francisco Bay Area are under threat due to the introduced pathogen Sudden Oak Death (Phytophthora ramorum), which is killing large swaths of Tanoak, and to a lesser extent live oak.

Stand replacing fires, especially in the southern portion of the range have drastically alter habitat, likely making it ill-suited for Craterellus atrocinereus in the near term, and is likely detrimental to this species, due to the limited populations and spore production for re-introduction. 

Habitat decline due to urban development.

Limit the spread of Sudden Oak Death in northern California forests.

Total extent of range, and population of this species, and more date to assess trends and threats.

Craterellus atrocinereus is a highly desired edible species, and is collected by hobbyist foragers, although not specifically targeted like the common relative, C. calicornucopioides.

Arora, D. 1986. Mushrooms Demystified. Ten Speed Press: Berkeley, CA. 959 p.

Frank, J.L. 2015. Nomenclatural Novelties. Index Fungorum 249: 1.

iNaturalist. 2021. http://www.inaturalist.org. Accessed on March 02.

Mushroom Observer. 2021. http://www.mushroomobserver.org. Accessed on March 02.

MyCoPortal. 2021. http://mycoportal.org/portal/index.php. Accessed on March 02.

Siegel, N. and Schwarz, C. 2016. Mushrooms of the Redwood Coast. Ten Speed Press: Berkeley, CA. 601 p.

Thiers, H.D. 1985. The Agaricales (Gilled Fungi) of California. 2. Cantharellaceae. Mad River Press: Eureka, CA. 34 p.